Ruaidri Ua Conchobair

Ruaidri Ua Conchobair (1116-2 December 1198), also known as Rory O'Connor, was King of Connacht from 1156 to 1186 (succeeding Toirdhealbhach Ua Conchobair and preceding Conchobar Maenmaige Ua Conchobair) and High King of Ireland from 1166 to 1198 (succeeding Muirchertach MacLochlainn and preceding Brian O'Neill).

Biography
Ruaidri Ua Conchobair was born in Connacht, Ireland in 1116, the son of Toirdhealbhach Ua Conchobair. In 1136 and 1143, he failed in his attempts to remove his brother Conchobar Ua Conchobair from his status as heir apparent, but Conchobar's assassination in 1144 and Ruaidri's battlefield victories against Connacht's rivals resulted in Ruaidri being appointed his father's heir in 1151. That same year, he successfully raided Munster, and he later divided Munster between the O'Brian and MacCarthy families, creating the separate states of Tuadmuma and Desmuma. In 1156, he became King of Connacht unopposed, and he had three of his 22 brothers arrested to prevent them from conspiring against him. In 1157, High King Muichertach MacLochlainn vassalized Mide, evicted the King of Osraige, subdued Munster, and captured Limerick, leading to Muichertach's enemies pleading to Ruaidri for assistance. Ruaidri plundered the area around Strabane and Derry, and he then defeated Muirchertach in order to become High King in 1166. That same year, he sent his ally Tighearnan O'Ruairc to attack the unpopular King of Leinster Dermot MacMurrough, who was forced to flee to Bristol. In 1169, Ruaidri and King Domnall Mac Gilla Patraic of Osraige allied against MacMurrough and his Norman allies at the start of the Norman invasion of Ireland; in 1170, the Normans took Dublin from the Irish. In 1175, Ruaidri was forced to agree to the Treaty of Windsor with King Henry II of England, paying tribute to England and allowing for the English to rule over the eastern half of Ireland as he ruled the western half of the island. He died in 1198.